New Clues to link between Tysabri and PML

[Remy9111]

Well here is a new article (from 2014) on Tysabri, PML, and the JCV antibody test. It also offers an algorithm for accessing risk given what your titer levels are. It looks like medscape is simply posting info from a 2014 journal article?

http://www.medscape.com/viewarticle/820968_4

This section I found a little disconcerting since I'm JCV-

"The false negative rate of the JCV serum antibody test is 2.5% [Gorelik et al. 2010]. A recent small study (n = 67) examined urine and serum for detection of JCV levels to evaluate the JCV serum antibody test and determined the false negative rate to be 37% [Berger et al. 2013]. Further studies are needed in larger numbers of patients to determine the significance of these findings. Monitoring of these patients should include periodic (most often every 3–6 months) rescreening of their antibody status as there is a 2–3% seroconversion rate annually for these patients."

It seems like they aren't completely certain about several thins, including this 37% false negative rate in one cluster of people? YIKES! Does anyone here get the antibody test every 3 months.

Also the article states that if you go off of Tysabri and get steroid pulses (to help prevent rebound) there is still a 30-50% you will have a relaspse within 6 months. That's news to me.

The article does stratify risk (and give numbers) for high positive and low positive on the JCV antibody test.

[ru4cats]

I am also JC-, and on my next test later this month, I will request my index level that will hopefully allow me to monitor my JC status more carefully.

I still am getting my tests every six months, and my neurologist is using the 2% number for seroconversions.

I know Biogen pays for JC tests at Quest Diagnostics once every six months, but I'm not sure if they'd pay for every three. I guess you could give them a call and find out.

[Special Kay]

My neurologist tests me for JCV every three months. They just draw blood before hooking me up for my infusion.

I've been negative consistently since I started (18 infusions). This time, I asked for the titer. I am 0.14.

My doctor did tell me that Biogen is refining the ranges based on emerging data. At first I thought my titer was great, but then when I thought about it, maybe it's a little too close to 0.2 which is considered "equivocal" or "indeterminate"?

I asked her if her center had had any patients with PML. This is a dedicated MS Center in New York City with a lot of patients (and quite a number on Tysabri, based on the infusion room). She said "Thank God, no!" She did have one patient, she said, who had such a bad rebound after coming off Tysabri that they feared it was PML.

For her patients that are JCV+ and still choose to take Tysabri, she does MRIs every three months. She says that there can be radiologic evidence of PML prior to symptoms.

[Special Kay]

I should also say that my neurologist also sees me for an exam every three months since I've been on Tysabri (previously on Avonex, I saw her every 6 months).

She is definitely pro-Tysabri, but I have to say, I find her caution to be comforting.